Drainage of the thoracic cavity has been accomplished by underwater drainage devices of unitized plastic construction for the past ten years or so. These devices are depicted in the prior art patents of Bidwell, U.S. Pat. Nos. 3,363,626, 3,363,627, and 3,559,647.
These devices use a classical collection chamber, a water seal chamber, and a suction control chamber. One major deficiency of these devices was overcome by Kurtz U.S. Pat. No. 3,683,913 which prevented loss of the water seal by means of a float valve. From this prior art came a commercial product known as the Deknatel Pleurevac A-4000 product which became the standard utilized product until the year 1980. The Pleurevac was favorably received in that it combined the main essential elements of collection, underwater seal, and suction control all in one unitized structure. The Pleurevac A-4000 however suffered some limitations in that it required a considerable amount of water to set up the device, limiting its use in the emergency room. The suction control required continual adding of water, which evaporated during use and it was noisy and disturbed patients. Due to the limitations of the water seal and suction control the A-4000 has to be over 18" in height making it difficult to position on the lower bed rail which is only 12" from the floor.
Attempts to overcome these above indicated deficiencies were proposed by the underwater drainage devices disclosed in recently issued U.S. Pat. Nos. 4,261,362, 4,296,748, and 4,312,351. All three of these patents disclose devices which still use an underwater seal. U.S. Pat. No. 4,261,362 discloses the use of the patient's own drainage to form a seal with dissolvable compartments in the collection chamber. There is no built in suction control. In U.S. Pat. No. 4,296,748 a separate suction control bottle attachable by means of a needle to the device shown in U.S. Pat. No. 4,261,362 was proposed as a necessary means of built in suction control. In both these devices a one-way valve is provided after the water seal to prevent loss of the water seal in the event of high negativity within the patient's pleural cavity. The valve does not and is not intended to act as a replacement for a water seal.
In Kurtz U.S. Pat. No. 4,312,351 an underwater. seal is provided as in U.S. Pat. Nos. 4,261,362 and 4,296,748 however, apparently recognizing that the high-negativity valve can become clogged due to its proximity of the water seal, this valve is isolated away from the body fluid seal to protect its function. None of the devices shown in these patents other than the original A-4000 device have ever been commercialized.
However in 1980, a new device was commercialized, called Thora-Klex, which was developed by two cardiovascular surgeons Doctors Elliott and Halseth. The Thora-Klex product was different than the prior art in that it replaced the water seal with a one-way valve and provided a mechanical suction control means instead of a water suction control means of the Pleurevac A-4000 and the Kurtz and Bidwell patents above described.
Thora-Klex was promoted as a "waterless" thoracic drainage device which was more convenient to set up, less cumbersome, lower in height, and did not have a water seal and did not need water for suction control.
Thora-Klex has been well received for use in emergency room situations in that it is easy to set up and does not require water for a water seal or suction control.
While Thora-Klex is an improvement in the state of the art, it suffers from some major deficiencies, both diagnostic and functional in character which makes it limited in use and, accordingly, the Pleurevac device even with its water requirements, is still considered the standard for general purpose nonemergency cardiovascular and thoracic surgery.